Lower tooth count ratchets

[Seanny]

Can lower tooth count ratchets handle more torque/stress than the higher count ratchets? It seems like the smaller the teeth are, the likelihood that they might slip is greater.


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[ChrisLS8]

Logic would say that's true and low tooth ratchets seem beefier however it's definitely not true, it's usually the opposite since the pawl engages more teeth

 

[JVB]

Logic would say that's true and low tooth ratchets seem beefier however it's definitely not true, it's usually the opposite since the pawl engages more teeth

Exactly, the lower tooth ratchets *usually* engage about 25% of what the 72+ tooth ratchets engage from what I have seen.

 

[PhysicsDude]

Yep, higher tooth count ratchets are usually quite a bit stronger, due to engaging multiple (usually 4 or 5) teeth at a time.

Although, there are several youtube videos of ratchets being tested to failure (including AvE's video) and the square drive usually sheers off before the ratcheting mechanism fails.

 

[turnthewrench 2.0]

Lots of variables in that equation but, generally, the more the merrier.

 

[Wamsutta]

It's the total contact surface area of the pawl to the gear that makes up the strength; and of course minimal clearance adds to the strength.

 

[Fedwrench]

Older ratchets in the 24-36 tooth range usually only had two to three teeth on the pawl gear meshing with the drive gear in each direction. Some Newer ratchets in the 60-90 tooth range often use a floating pawl gear that can have 7-11 teeth meshing with the drive gear. makes for a stronger design.

 

[seanb02]

How about when comparing a pear head style to a round head style? My regular tooth count SK round heads have taken a beating and still ratchet like new. I have one 12" 1/2" drive ratchet that has had a pipe on it more times than not and the handle is bent like you wouldn't believe but the mechanism still works great.

Had a pear head Powerbuilt ratchet 1/2" drive 18" long that I put a cheater pipe on and it blew the guts apart on it first try. Likely better quality components is a large factor, but it seems as though the round head ratchets are a stronger design even though more bulky in a lot of situations than a fine tooth pear head.

 

[Steiger9]

We've got three or four of those old low tooth count open head Indestro/Thorsen ratchets here on the farm. Belonged to my grandpa and I would be surprised if my future grandkids aren't using them someday. Seems to be a very strong design. Would be interesting to see them included in a strength test. Except that I don't think they're made anymore.

 

[gtlaw]

 

[jdlong]

A lot has to with the quality of the tooth cut on the pawl and/or gear. Even with high tooth count, some have a tendency to loose their tooth engagement and skip under high torque.

 

[bonneyman]

You'd think that it'd be like bolt threads - more threads per inch equates to more contact area and thus more overall strength for a given size. But in actual practice that doesn't appear to be so with ratchets.

My opinion: ratchet strength is just as much (if not more) design and geometry than teeth number. I've not done any actual testing, but examination of the many worn or broken Bonney ratchets I've come across lead me to think that they are designed so the pawl "jams" at a certain point. At this point in rotation the pawl transmits the high load forces to a specific area when it "locks" the mechanism upon tightening. When worn - even by a few thousandths of an inch - the geometry changes significantly, and the pawl either splits (see-saw pawls), or moves enough in an unwanted direction (tic-toc and sliding pawls) that allows the teeth to slip.

 

[65k10]

Huh. Didn't realize the Facom roundheads (in this case Proto) were that strong.

I do see how fine tooth ratchets should be stronger, but in practice there is one small thing I have noticed. Once in a great while, I've had a Snap On 1/2 Dual 80 and a Gearwrench 1/2 84T skip a tooth just as I was starting to apply force. I assume the pawl hadn't quite got seated. Not a big deal and it doesn't negate the fact that they should be stronger than coarse tooth ratchets.

 

[turnthewrench 2.0]

Huh. Didn't realize the Facom roundheads (in this case Proto) were that strong.

I believe 13 or 14 teeth are in contact with gear. They're very strong.

 

[65k10]

I believe 13 or 14 teeth are in contact with gear. They're very strong.

Makes sense looking at the mechanism. I guess they are such a small and light ratchet I always thought they were kind of fragile. I'm surprised how much abuse it took.